title: Promoting effects of polychlorinated biphenyls (Aroclor 1254) and polychlorinated dibenzofuran-free Aroclor 1254 on diethylnitrosamine-induced tumorigenesis in the rat.
abstract: The hepatic tumor-promoting activity of a commercial polychlorinated biphenyl mixture, Aroclor 1254 (AR 1254), with and without its intrinsic polychlorinated dibenzofuran (PCDF) impurities, was investigated. Male Sprague-Dawley non-inbred albino rats were treated with 66 microgram diethylnitrosamine (DENA)/ml drinking water for 5 weeks and subsequently given a control diet or a diet supplemented (100 ppm for 18 wk) with either AR 1254 or AR 1254 from which the PCDF moieties were removed (AR 1254-PCDF). Of those animals receiving DENA alone, 16% exhibited hepatocellular carcinomas. Of those rats treated with DENA followed by administration of AR 1254 or AR 1254-PCDF, 64 or 84%, respectively, developed hepatocellular carcinomas. Thus promotion with either AR 1254 or AR 1254-PCDF significantly (P less than 0.05) increased the incidence of DENA-initiated hepatocellular carcinomas. Administration of AR 1254 or AR 1254-PCDF alone did not induce hepatic tumors. Therefore, PCDF impurities were not necessary for the promoting activity of AR 1254.
mesh_terms: D000818:Animals; D001140:Aroclors / Q000008:administration & dosage / Q000494:pharmacology*; D001572:Benzofurans / Q000494:pharmacology; D001835:Body Weight / Q000187:drug effects; D002273:Carcinogens; D020111:Chlorodiphenyl (54% Chlorine); D003043:Cocarcinogenesis; D004032:Diet; D004052:Diethylnitrosamine; D008099:Liver / Q000187:drug effects / Q000473:pathology; D008113:Liver Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008114:Liver Neoplasms, Experimental / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D011078:Polychlorinated Biphenyls / Q000494:pharmacology*; D051381:Rats
chemical_list: D001140:Aroclors; D001572:Benzofurans; D002273:Carcinogens; D020111:Chlorodiphenyl (54% Chlorine); D004052:Diethylnitrosamine; C023614:dibenzofuran; D011078:Polychlorinated Biphenyls